Proof and Percent

Proof is a term used in the United States to express alcohol concentration of a distilled alcoholic beverage.All non distilled beverages are labeled as Percent alcohol by volume. The proof of any beverage is double its percent alcohol concentration. A 100 proof whiskey contains fifty (50) percent alcohol, while an 86 proof whiskey would contain forty-three (43) percent alcohol and so forth. Beer is approximately four (4) percent alcohol, therefor, its proof equivalent would be 8 proof.

The term Proof exists as a result of folklore. Prior to the process of aging in charred oak barrels, whiskey was a clear liquid. In the early frontier days, individuals could water down the whiskey and the buyer would not be able to visually tell the difference. To ensure that the buyer was receiving a good product, a simple test was developed. The buyer would mix equal parts of whiskey with black gunpowder and strike a match to the solution. If this mixture burned with a steady blue flame, this was "proof" that the shipment was potent or good.

By knowing the proof of percent of a beverage, one can calculate the actual amount of alcohol contained in a drink or series of drinks. By taking the amount of the alcoholic beverage (V) and multiplying that number by the percent alcohol (%) the ounces of ethanol contained in that beverage can be determined.

Beer is normally four (4) percent, to calculate the amount of ethanol in one twelve (12) ounce can or bottle of beer, V = 12, % = 4, which must be converted to its decimal equivalent = .04.

12 x .04 = .48

Accordingly, one 12 ounce can or bottle of 4% beer will contain .48 ounces of ethanol.

To compute the amount of ethanol in one ounce of 100 proof whiskey, the first step is to convert the proof to percent. 100 proof is equal to 50 %. Converting 50% to its decimal equivalent equals .50 and V = 1.

1 x .50 = .50

Thus, a one ounce serving of 100 proof whiskey will contain .50 ounces of ethanol.